The present invention relates to a semiconductor device, a control system, and an observation method, and to, for example, a technique for observing surroundings by a plurality of radars.
Japanese Patent No. 4917270 discloses a radar device that aims to correctly combine search data items obtained from a plurality of radar antennas and display combined data item on a single indicator. In this radar device, search data generating means generates search data items in a polar coordinate system from respective search signals generated by the plurality of radar antennas. Correlation processing means performs correlation processing on the search data items and stores processed data items as correlation processed data items in a Cartesian coordinate system. Display image data selecting means selects the correlation processed data item corresponding to a particular antenna in a region corresponding to the particular antenna and outputs it to display image data storage means. In other regions, the display image data selecting means selects the correlation processed data items corresponding to antennas other than the particular antenna and outputs them to the display image data storage means.
However, the present inventor has found a problem in the technique disclosed in Japanese Patent No. 4917270, that as a correlation processed data item in the Cartesian coordinate system is generated for each radar antenna, a necessary storage capacity of a memory will become large. This is because an amount of data in the Cartesian coordinate system is greater than that of data in the polar coordinate system.
Japanese Patent No. 3990830 discloses a radar video composing device that aims to generate composite radar video signals even when radar antennas are installed at different places, and in addition, when transmission of radio waves and rotation of the radar antennas are asynchronous between the radar antennas. In this radar video composing device, an Rθ-XY conversion circuit converts video signals sent from radars A and B into Cartesian coordinate data items and stores them in a memory as image data items. An XY-Rθ conversion circuit adjusts the image data items of the radars A and B with respect to a center position of the radar A and converts the image data items into polar coordinate data items. Then, an output buffer control circuit 19 combines the polar coordinate data items of the respective radars A and B and outputs a combined data item.
However, the present inventor has found a problem in the technique disclosed in Japanese Patent No. 3990830, that as a Cartesian coordinate data item is generated for each radar antenna, in a manner similar to the technique disclosed in Japanese Patent No. 4917270, a necessary storage capacity of a memory will become large. The present inventor has found another problem in the technique disclosed in Japanese Patent No. 3990830 that as the data items are converted into the Cartesian coordinate data items, and then the Cartesian coordinate data items need to be converted again into the polar coordinate data items, this processing takes time.